In all the above cases the elements have united atom for atom. Some elements will not so unite. In CaCl2 how many atoms of each element? Parts by weight of each? Give molecular weight. Is the size of the molecule thereby changed? Name these, give the number of atoms of each element in the molecule, and the proportion by weight, also their molecular weights: AuCl3, ZnCl2, MnCl2, Na2O, K2S, H3P, H4C. Principal Elements. Name. Sym. At. Wt. Valence. Vap.D. At.Vol. Mol.Vol. State. Aluminium Al 27. II, IV ... ... ... Solid Antimony Sb 120. III, V. ... ... ... " Arsenic As 75. III, V 150. " Barium Ba 137. II ... ... ... " Bismuth Bi 210. III, V ... ... ... " Boron B 11. III ... ... ... " Bromine Br 80. I, (V) 80. Liquid Cadmium Cd 112. II 56. Solid Calcium Ca 40. II ... ... ... " Carbon C 12. (II), IV ... ... ... " Chlorine Cl 35.5 I, (V) 35.5 Gas Chromium Cr 52. (II),IV,VI ... ... ... Solid Cobalt Co 59. II, IV ... ... ... Gas Copper Cu 63. I, II ... ... ... " Fluorine F 19. I, (V) ... ... ... Gas Gold Au 196. (I), III ... ... ... Solid Hydrogen H 1. I 1. Gas Iodine I 127. I, (V) 127. ... ... Solid Iron Fe 56. II,IV,(VI) ... ... ... " Lead Pb 206. II, IV ... ... ... " Lithium Li 7. I ... ... ... " Magnesium Mg 24. II ... ... ... " Manganese Mn 55. II, IV, VI ... ... ... " Mercury Hg 200. I, II 100. Liquid Nickel Ni 59. II, IV ... ... ... Solid Nitrogen N 14. (I),III,V 14. Gas Oxygen O 16. II 16. " Phosphorus P 31. (I),III, V 62. Solid Platinum Pt 197. (II), IV ... ... ... " Potassium K 39. I ... ... ... " Silicon Si 28. IV ... ... ... " Silver Ag 108. I ... ... ... " Sodium Na 23. I ... ... ... " Strontium Sr 87. II ... ... ... " Sulphur S 32. II,IV,(VI) 32(96) " Tin Sn 118. II, IV ... ... ... " Zinc Zn 65. II 32.5 "